topgallant sail

noun Nautical.

1. a sail or either of two sails set on the yard or yards of a topgallant mast.

noun

1. Also called: topgallant mast a mast on a square-rigger above a topmast or an extension of a topmast
2. Also called: topgallant sail a sail set on a yard of a topgallant mast
3. (modifier) of or relating to a topgallant